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emvnuel

lombok-patterns

by emvnuel

0🍴 0📅 Dec 28, 2025

SKILL.md


name: lombok-patterns description: Lombok annotations and best practices for Java 21+ projects. Use when reducing boilerplate, configuring builders, or choosing between Lombok and Records.

Lombok Patterns

This skill provides guidance on using Project Lombok to reduce boilerplate code in Java applications, covering annotations, best practices, and integration patterns.

Note: This guide targets Java 21+ projects. Some Lombok features are now obsolete due to modern Java features (Records, var, try-with-resources). See Java 21+ Considerations below.

Overview

Lombok is a Java library that automatically generates common code like getters, setters, constructors, builders, and more during compilation. It helps create cleaner, more maintainable code.

Java 21+ Considerations

Some Lombok features are now redundant with modern Java:

Lombok FeatureJava AlternativeRecommendation
val/varvar (Java 10+)Use Java var
@Valuerecord (Java 16+)Prefer records for simple value objects
@Datarecord (Java 16+)Prefer records for simple DTOs
@Cleanuptry-with-resources (Java 7+)Use try-with-resources
@Withrecord wither methodsRecords can define wither methods

When Lombok Still Adds Value

  • JPA Entities: Records don't work with JPA (need no-arg constructor, mutable state)
  • @Builder: Records don't have built-in builder support
  • @Slf4j: No Java equivalent for logger generation
  • @RequiredArgsConstructor: Useful for Spring dependency injection
  • Inheritance: Records can't extend classes

Annotation Categories

Core Annotations (Still Valuable)

AnnotationPurposeUse Case
@Getter/@SetterAccessor methodsJPA entities, mutable classes
@NoArgsConstructorNo-argument constructorJPA entities, serialization
@AllArgsConstructorAll-fields constructorDependency injection
@RequiredArgsConstructorConstructor for final/@NonNull fieldsSpring services
@BuilderBuilder pattern implementationComplex object construction

Consider Java Records Instead

LombokUse Java Record When
@ValueSimple immutable data carriers
@DataSimple DTOs without inheritance
// ✅ Prefer Java Record for simple value objects
public record Money(BigDecimal amount, String currency) {}

// ✅ Prefer Java Record for simple DTOs
public record CustomerDTO(String name, String email) {}

// ✅ Use Lombok for JPA entities (records don't work with JPA)
@Entity
@Getter
@Setter
@NoArgsConstructor
public class Customer {
    @Id private Long id;
    private String name;
}

Logging Annotations

AnnotationLogger Type
@Slf4jSLF4J (recommended)
@Log4j2Log4j 2
@Logjava.util.logging
@CommonsLogApache Commons Logging

Field & Method Annotations

AnnotationPurpose
@NonNullNull checks on parameters/fields
@WithImmutable setters (creates new instance)
@SneakyThrowsThrow checked exceptions without declaration
@SynchronizedThread-safe method synchronization
@ToStringCustomizable toString() generation
@EqualsAndHashCodeCustomizable equals/hashCode

Quick Reference

@Entity
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode(onlyExplicitlyIncluded = true)
public class Product {
    @Id
    @EqualsAndHashCode.Include
    private Long id;

    private String name;
    private BigDecimal price;
}

Spring Services

@Service
@RequiredArgsConstructor
@Slf4j
public class OrderService {
    private final OrderRepository orderRepository;
    private final PaymentService paymentService;

    public Order process(Order order) {
        log.info("Processing order: {}", order.getId());
        return orderRepository.save(order);
    }
}

Builder Pattern (Lombok Adds Value)

// Records don't have builder support - use Lombok
@Builder
public record Email(
    String to,
    String subject,
    String body,
    @Singular List<String> attachments
) {}

// Usage
Email email = Email.builder()
    .to("user@example.com")
    .subject("Hello")
    .body("Content")
    .attachment("file1.pdf")
    .build();

Best Practices

✅ Do

  • Use Java Records for simple value objects and DTOs
  • Use @RequiredArgsConstructor with final fields for dependency injection
  • Use @Slf4j for logging instead of manual logger creation
  • Use @Builder for classes with many optional fields
  • Be explicit with @EqualsAndHashCode on JPA entities

❌ Avoid

  • Using @Data or @Value when a Java Record would suffice
  • Using @Data on JPA entities (use individual annotations)
  • Using @EqualsAndHashCode with lazy-loaded JPA relationships
  • Overusing @SneakyThrows (makes exception handling unclear)

Common Pitfalls

PitfallProblemSolution
@Data on entitiesIncludes mutable setters, problematic equals/hashCodeUse @Getter, @Setter, explicit @EqualsAndHashCode
Missing @NoArgsConstructorJPA/Jackson need no-arg constructorAlways add with @AllArgsConstructor
Circular @ToStringStackOverflow with bidirectional relationshipsUse @ToString.Exclude on one side
Using Lombok for simple DTOsAdds unnecessary dependencyUse Java Records instead

Cookbook Index

Core Annotations

Field & Method Annotations

Integration Patterns

Score

Total Score

35/100

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